Double spool flow feedback valve



Dec. 12, 1961 R. AMBROSINI 3,012,577

DOUBLE SPOL FLOW FEEDBACK VALVE Filed Deo. 31. 1959 2 Sheets-Sheet 1LEONARD R. AMBROSINI AGENT Dec. 12, 1961 Filed Deo. 31, 1959 fle@ @o @aL. R. AMBROSINI DOUBLE SPOOI.. FLOW FEEDBACK VALVE 2 Sheets-Sheet 2 IN VEN TOR.

LEONARD R. AMBROSINI AENT United States Patent O 3,012,577 DOUBLE SPOULFLOW FEEDBACK VALVE Leonard R. Ambrosini, Los Angeles, Calif., assignerto Lear, Incorporated Filed Dec. 31, 1959, Ser. No. 863,355 Claims. (Cl.137-622) This invention relates to hydraulic valves and moreparticularly to two-stage hydraulic valves having a hydraulic feedback.

In the past, two-stage hydraulic valve systems have utilized some meansof feedback from the second stage to the first stage to indicate themovement or response of the second stage. One method of accomplishingthis feedback has been by mechanical means. That is, the second stagevalve member is mechanically connected to the first stage and thereforeany movement of the second stage is fed back to the first stage. Thedisadvantage of the mechanical feedback system is that it is verycomplex, costly and requires extra space. A second known method offeedback between a ilrst and second valve is the pressure transducer,but again, the pressure transducer requires extra space, adds morecomplexity to the system and increases the cost of the system. It isalso possible to use an electric pickoff on the valve member of theSecond stage to provide an electrical signal proportional to themovement of the valve member of the second stage. The electrical signalis picked up by a motor or other electrical operating mechanism which inturn operates the valve member of the first stage. The disadvantage ofan electric pickof is that the electric pickoff is more subject tofailure than is a hydraulic feedback and the electric pickoiic is,again, more complex and more costly.

It is therefore an object of this invention to provide a two-stagehydraulic valve system requiring no external feedback.

It is another object of this invention to provide a hydraulic valvehaving hydraulic feedback.

Still another object of this invention is to provide a hydraulic valvewhich operates on a mechanical or electrical input and has hydraulicfeedback.

Still another object of this invention is to provide a feedback from thesecond valve to the rst, which really represents the iiuid flowfurnished by the second stage valve to the actuator. l

Other objects and advantages of the present invention will becomeapparent from the following description when taken in conjunction withthe drawings, in which:

FIGURE 1 is a cross section of the present invention; and

FIGURE 2 is a cross sectional view of a second embodimentl of thepresent invention.

Referring now to FIGURE 1, there is shown a first valve body whichcontains a valve cylinder 11 and valve member 12 reciprocally movable invalve cylinder 11. A mechanical lever 13 is mechanically connected toand drives the valve member 12 longitudinally within valve cylinder 11.The mechanical lever 13 may be operated by any means, e.g., a motor. Thevalve body 10 has an input port 14 and two return ports 15 and 16. Thevalve member has four portions 17, 18, 19 and 20 spaced longitudinallyand connected by a shaft 21. The input port 14 is positioned between theportions 18 and 19 of the valve member 12 and the return ports 15 and 16are positioned between the portions 17 and 18 and 19 and 20,respectively. The valve body 10 has a further passage 22 connected toboth ends of the valve cylinder 11 by passages 23 and 24. Ports 25 and26 are located on either Vside ofY input port 14 and are connected tothe Yvalve cylinder 11. Note that the ports 25 and 26 do not connect tothe passage 22. An orifice 27 is positioned in passage 22and locatedbetween the passages 23 and 24.

The input port 14 is connected by suitable conduit 30 to a fluid supply31. The return ports 15 and 16 are connected by suitable conduit 32 tothe fluid supply 31. Since the valve member 12 is in the neutralposition, the valve portions 18 and 19 restrict the liow of uid from theinput port 14 to the passages 25 and 26. However, if the lever 13 movesthe valve member 12 longitudinally one way or the other, the incomingfluid entering the port 14 is allowed to pass to either passage 25 orpassage 26, depending upon which Way the valve member 12 is moved.

A second valve body 33 contains a second valve cylinder 34 and a secondvalve member 35 reciprocally movable in valve cylinder 34. The valvemember 35 also has four portions 36, 37, 38 and 39 spaced longitudinallyand connected by shaft 40. The Valve body 33 has an inlet port 41connected to the liuid pressure source by way of suitable conduit 42 andconduit 2S. The port 41 is positioned between the sections 37 and 38 ofthe valve member 35. The valve body 33 also has two return ports 43 and44 connected to the iiuid supply 31 by Way ofthe housing 50. The pistoncylinder 51 has a port 54 located at one end and a'port 55 located atthe other end of cylinder 51. The port I54 is connected to port 49 bysuitable conduit 57.

In operation, the lever 13 or any other means for actuating valve member12 moves the valve member 12, for example, to the right, causing iiuidto flow through the port 25, conduit 46 and into cylinder 34 to create apressure against the portion 39 of the valve member causing the valvemember 35 to move to the left as seen in the drawing, which in turncauses the fluid entering port 41' connected to the cylinder 11transmits the pressure dif-v ferential to the portion 20 of valveVmember 12, urging the valve member 12 to the left, as seen in thedrawing, to close off the outlet port 25.l At the same time, the piston52 and shaft 53 are driven to the right by the uid flow. The fluid onthe other side of the piston 52 passes through port 55 and conduit 57into cylinder 34 and then to the iiuid supply by way of port 43 andconduits 45 and 32. It can be seen that for a given flow of fluidthroughthe orifice 27, a given amount of pressure will exist on theposition Z0 of valve member 12 thus counteracting the initial urgingforce on valve member 12 produced by motor 13. The port 25 will remainopen until the iiow of tiuid against the valve member 12 is suicient tourge' the valve member 12 in a position to close the port 25. Once thevalve member 12 has returnedto `the neutral position, anyfurtherpressure on the portion causes-valve member 12 to open the port26 which in turn causes the f Y valve member 35 to move to the right toshut off the ow of fluid to the piston 52. Hence, the piston 51 receivesa given amount of pressure from the iiuid iiow for a given movement ofvalve member 12.

If now the motor 13 drives the valve member 12' to the i,

left as seen in the drawing, the uid entering the port 14 passes throughthe port 26 and then through the con duit 47 l'against the portion 36 ofthevvalve member 35 Patented Dec. 1 2, 1961` A shaft 53 is connected toone side of piston 52 and extends throughI 57 to the piston cylinder 51to urge the piston 52 and shaft 53 to the left. The fluid on the otherside of the piston 52 is forced out port 54 through the conduit 56 andorifice 27, passage 22, conduit 58 and port 48 to the return port 44.The return fluid flow from the piston 52 in passing through the orifice27 again sets up a pressure differential. The pressure differential atthe opposite ends of the orifice 27 is transmitted to the portion 17 ofvalve member 12, therefore urging the valve member 12 to the right inopposition of the urging of the motor 13. When the pressure on theportion 17 of valve member 12 is sufli cient to close the port 26 thenthe valve member 35 returns to a neutral position and maintains thepiston 52 in a new position.

It is to be noted that the orifice 27 is small, in the range from .0l to.1 inch in diameter, so that the differential pressure on either side ofthe orifice is established as soon as valve member moves from theneutral position. For a typical supply pressure of the fluid, e.g., 3000p.s.i., and for a typical differential pressure on the opposite ends ofthe orifice of 100 p.s.i., the rate of flow through the orifice, if theorifice is, for example, .05 inch in diameter, will be approximately onegallon per minute, depending upon the characteristics of the design.

It can be seen then that by the above method there is provided ahydraulic feedback proportional to the rate of flow of fluid through theorifice 27.

Note, also, that in place of the passage 22 and orifice 27, it ispossible to make a hole in the shaft 21 to serve the same purpose.

FIGURE 2 shows a further modification of the present invention wherein avalve body 59 has a valve cylinder 60 therein and an enlarged portion 61of valve cylinder 60. A valve member 62 is reciprocaliy movable withinvalve cylinder 60. The valve member 62 has two pistons 63 and 64, and aspool member 65 connected by shaft 66. The valve body '59 has an inletport 67 positioned between the portion 64 and 65 of the valve member 62and a return port 68 positioned between the portion 63 and 65 of valvemember 62. The valve body 59 also has two outlet ports 69 and 70. Theoutlet port 69 is positioned between the inlet port 67 and the returnport 68 and the outlet port 70 is positioned between the portion 64 and65 of valve member 62. The valve housing 59 also has a passage 71therein. The end of piston 63 of valve member 62 is hydraulicallyconnected to the inside portion of the piston 64 of valve member 62 byway of passages 72, 71 and 73. Enlarged portion 61 of valve chamber 60is connected by suitable conduit '79 to one end of the piston cylinder51. In the case of .FIGURE 2, itisV necessary to modify the valve member35 so that one end portion is larger than the other and so that a largerfluid flow to the smaller end balances a smaller fluid flow to thelarger end and maintains the valve member 35 in a neutral position. Therest of the device shown in FIG- URE 2 is substantially the same as thatshown in FIG- URE l.

To understand the operation of FIGURE 2, first consider that the valvemember 61 is in a neutral position when the portion 65 of valve member62 is positioned so that there is a small opening to the outlet port 69and there is a balance of pressure on both ends of valve member 35. Ifthe torque motor moves valve member 62 to the right, more fluid entersthe input port 67 and passes to the outlet port 69, to the portion 39 ofvalve member 35 causing the valve member 35 to move to the left, as seenin the drawing, thereby causing the fluid entering port 41 of the valvebody 33 to pass to the outlet port 48 of the valve body 33 through theconduit 58 to the passage 71. The fluid in passage 71 will pass throughthe port 73, through the space 75 around piston 64 then through theconduit 55 and into the piston chamber 51. The fluid on the other sideof piston 52 is forced to the return port 43 by way of conduit 57 andport 4S. The fluid asgit flows through theopening 75 around the piston64 creates a differential pressure between the passage 73 and theconduit 741. The differential pressure acts on the piston 64 in adirection to urge the valve member 62 to the right to close the port 69.lf the valve member 62 moves beyond the neutral point while moving tothe right, the pressure in the port 69 is exposed to the return port 68thereby decreasing the pressure on one side of the valve member 35causing the valve member 35 to return to the neutral position which inturn decreases the pressure on the valve member 62 and causes the valvemember 62 to also return to the neutral position. A movement of thevalve member 62 to the left, caused by the motor 13, tends to close port69 causing an unbalance of pressure on valve member 35 which causesvalve member 35 to move to the right causing fluid flow from the intakeport 41 to flow to the outlet port 49 and to the piston chamber 51 bythe way of the conduit 57 and port 55. The back pressure or flow offluid on the opposite side of the piston 52 causes fluid to flow inconduit 74 and around the piston 64. Again, the differential pressurecreated by the fluid flowing around the small opening around piston 64causes the differential pressure to be transmitted to the piston 64 in adirection to urge the valve member 62 to the right to open the port 69and again put a balance of pressure on the valve member 34 to return thevalve member 34 to the neutral position.

It can be seen that the device shown in FIGURE 2 provides a hydraulicfeedback proportional to the rate of flow of the fluid around the piston64.

Although the invention has been described and illustra'ted in detail, itis to be clearly understood that the same is by way of illustration andexample only and is not to be taken by way of limitation, spirit andscope of this invention being limited only by the terms of the appendedclaims.

I claim:

l. A valve system comprising a fluid pressure source, a first valvemeans connected to said fluid pressure source, a second valve meanshydraulically connected to said fluid pressure source and said firstvalve means such that said second valve means is responsive to theoutput of said first valve means, means to actuate said first valve, theoutput of said second valve being connected by way of an orifice to aload, conduit means connecting one end of said first valve means to oneside of said orifice and the other end of said rst valve means to theother side of said orifice such that fluid flow through said orificecreates a pressure differential on either side of said orifice which isapplied to the ends of said first valve means to operate said firstvalve means in opposition to the mechanical input means to operate saidfirst valve.

2. A two-stage valve system comprising a first valve body having a firstvalve member reciprocally movable therein, an inlet port and two outletports in said first valve body wherein said first valve member controlsthe flow of fluid between said inlet port and said outlet ports, asecond valve body having a second valve member reciprocally movabletherein wherein said second valve body has an inlet port and tworegulated outlet ports and said second valve member controls the flow offluid between said inlet port and said two regulated outlet ports,suitable conduit connecting said outlet ports of said first valve bodyto the ends of said second valve member such that second valve member isresponsive to the output of said first valve body, said second valvebody having suitable outlet conduit and an orifice in said outletconduit of said second valve body and means for hydraulically connectingone end of said first valve member to one side of said orice and theother end of said first valve member to the other side of said orificesuch that fluid flow through said orifice creates a differentialpressure between the opposite ends of said orifice and said differentialpressure is transmitted to one end of said first valve member. v

3. A two-stage valve system comprising a first valve body having a valvecylinder therein and a valve member reciprocally movable within saidvalve cylinder, said first valve body having provisions for an inlet andtwo outlet ports whereby said first valve member controls the flow offluid from said inlet port to outlet port, said first valve memberhaving a passage therethrough from one end of said first valve member tothe other end of said first valve member, a second valve body having asecond valve cylinder therein and a second valve member reciprocallymovable within said second valve body, said second valve body having theprovisions of an inlet port and two outlet ports, said second valvemember controlling the flow of fluid from said inlet port to said twooutlet ports of said second valve body, one of said outlet ports of saidsecond body being hydraulically connected to one end of said first valvemember by means of suitable conduit, the other outlet port of saidsecond valve body being hydraulically connected to the other end of saidfirst valve member by suitable conduit, said second valve member beingresponsive to the output of said first valve body whereby the output ofsaid second valve body passing through said iirst valve member creates adifferential pressure on either end of said first valve member so thatsaid first valve member is urged in a direction to move said first valvemember in a position to close said outlet ports of said first valvebody.

4. A two-stage valve system comprising a first valve body having a rstvalve member reciprocally mov-able therein, said first valve body havingan inlet port and two outlet ports positioned between the ends of saidfirst valve member, said iirst valve member controlling the flow offluid between said inlet ports and said outlet ports in said first valvebody, the ends of said first valve member extending into respectivechambers such that one of the ends of said first valve member extendsinto an enlarged chamber whereby said enlarged chamber has an inlet andoutlet port and said one end of said valve member is positioned betweensaid inlet and outlet ports with a gap between said one end or" saidvalve member and the walls of said chamber such that liuid may flow fromsaid inlet port of said chamber to said outlet port of said chamber,torque means to operate said first valve member, a second valve bodyhaving a second valve member reciprocally movable therein, said secondvalve member being responsive to the output of said first valve bodywhereby the output of said second valve body is connected by suitableconduit to the input and output ports of said enlarged cylinder suchthat flow of fluid out of said second valve body and around said one endof said valve member causes a differential pressure on either side ofsaid first valve' member thereby urging said first valve member in adirection opposite to the urging of said torque means.

5. A hydraulic valve system comprising, a first valve body and a firstvalve member reciprocally movable therein, said first valve body havingthe provisions of an inlet port, two return pressure ports -and tworegulated pressure ports, said valve member controlling the flow of duidbetween said inlet port and said two regulated pressure ports, meansmechanically connected to said valve member to operate said valve memberwithin said valve body, a second valve body and a second valve memberreciprocally movable therein, said second valve body having theprovisions of two inlet ports connected respectively to said tworegulated pressure outlet ports of said first valve body such that saidregulated input ports of said second valve body are connected to eitherend of said body whereby said second valve member is positioned betweensaid two inlet ports, a third inlet port within said second valve body,two lreturn ports within said second body, valve body and two regulatedpressure outlet ports within said second valve body, a housing having achamber therein and a piston movably mounted Within said chamber,suitable conduit connecting one of said two regulated outlet ports fromsaid second valve member to one side of said piston chamber, suitableconduit connecting the other of said two regulated outlet ports of saidsecond valve member to the other side of said piston `chamber by way ofan orice in said suitable conduit connecting said other regulated outletport of said valve member to said other side of said piston cylinder,said rst valve body'having ports therein on either side of said valvemember and suitable conduit connecting said ports on either side of saidvalve member to said conduit connecting said second regulated pressureoutlet ports of said second valve body wherein said orifice ispositioned betwcen'said ports on either side of said valve member insaid first body, said first valve member moving in response to saidmechanical means, said second valve member moving in response tomovement of said first Valve member and said piston moving in responseto said second valve member to force fluid through said orifice therebycreating a differential pressure on the opposite ends of said orifice,said differential pressure being transmitted to one end lof said firstvalve member to urge said first valve member in a direction opposite theurging of said mechanical operating means.

References Cited in the file of this patent UNITED STATES PATENTS1,952,690 Strom Mar. 27, 1934 2,689,548 Holm et al. Sept. 2l, 19542,717,652 Nichols Sept. 13, 1955

